This work's purpose is to examine aging's influence upon the development and enactment of automatic and effortful informational/attentional cognitive processes. This purpose is accomplished through controlled laboratory studies. A study investigating the development of automatic visual detection of representatives of semantic categories was carried out on 7 young, 7 middled-aged, and 5 elderly subjects. The task was visual search in which one to three sematic categories were firse memorized and searched for in a series of two word visual displays. Automatic detection was defined as having occurred when the time for detection was equal regardless of the number of categories memorized. All subjects underwent 4200 training trials with the result that all young and middle-aged subjects developed automatic detection, 64 to 69 years old showed "partial" automatized ditection, and the three subjects 71 to 88 years did not show any automatized detection of memorized categories. The 71-88 years olds received an additional 2100 training trials and still did not show any evidence of automatization. It now remains to explain the loss of the automatization process in visual detection in 70+ year old individuals. To this end three additional experiments will be carried out. The first will present 70+ year olds with a very simple visual search task which will involve a search for numbers and an alphabetic letter or two letters. It is expected that automatization of detection will occur here and hence demonstrate that 70+ year olds can achieve it. The second study will investigate different methods of training. The third study will investigate the extent to which previously learned automatic processes, arithmetic addition and multiplication, have been retained. This project's significance lies in describing and explaining maturational changes in the development of automatic visual detection which is so important in our daily lives.